src/tt.h

   1 /*
   2   Glaurung, a UCI chess playing engine.
   3   Copyright (C) 2004-2008 Tord Romstad
   4
   5   Glaurung is free software: you can redistribute it and/or modify
   6   it under the terms of the GNU General Public License as published by
   7   the Free Software Foundation, either version 3 of the License, or
   8   (at your option) any later version.
   9
  10   Glaurung is distributed in the hope that it will be useful,
  11   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13   GNU General Public License for more details.
  14
  15   You should have received a copy of the GNU General Public License
  16   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19
  20 #if !defined(TT_H_INCLUDED)
  21 #define TT_H_INCLUDED
  22
  23 ////
  24 //// Includes
  25 ////
  26
  27 #include "depth.h"
  28 #include "position.h"
  29 #include "value.h"
  30
  31
  32 ////
  33 //// Types
  34 ////
  35
  36 /// The TTEntry class is the class of transposition table entries.
  37
  38 class TTEntry {
  39
  40 public:
  41   TTEntry();
  42   TTEntry(Key k, Value v, ValueType t, Depth d, Move m, int generation);
  43   Key key() const { return key_; }
  44   Depth depth() const { return Depth(depth_); }
  45   Move move() const { return Move(data & 0x7FFFF); }
  46   Value value() const { return Value(value_); }
  47   ValueType type() const { return ValueType((data >> 20) & 3); }
  48   int generation() const { return (data >> 23); }
  49
  50 private:
  51   Key key_;
  52   uint32_t data;
  53   int16_t value_;
  54   int16_t depth_;
  55 };
  56
  57 /// The transposition table class.  This is basically just a huge array
  58 /// containing TTEntry objects, and a few methods for writing new entries
  59 /// and reading new ones.
  60
  61 class TranspositionTable {
  62
  63 public:
  64   TranspositionTable(unsigned mbSize);
  65   ~TranspositionTable();
  66   void set_size(unsigned mbSize);
  67   void clear();
  68   void store(const Position &pos, Value v, Depth d, Move m, ValueType type);
  69   const TTEntry* retrieve(const Position &pos) const;
  70   void new_search();
  71   void insert_pv(const Position &pos, Move pv[]);
  72   int full();
  73
  74 private:
  75   TTEntry* first_entry(const Position &pos) const;
  76
  77   unsigned size;
  78   int writes;
  79   TTEntry* entries;
  80   uint8_t generation;
  81 };
  82
  83
  84 ////
  85 //// Constants and variables
  86 ////
  87
  88 // Default transposition table size, in megabytes:
  89 const int TTDefaultSize = 32;
  90
  91
  92 #endif // !defined(TT_H_INCLUDED)